This invention relates to a time division multiplex communication device for time division multiplexing a plurality of low-speed signal sequences into a plurality of high-speed signal sequences and/or for time division demultiplexing a plurality of high-speed signal sequences, into which a plurality of low-speed signal sequences are time division multiplexed, into the original low-speed signal sequences. A device according to this invention is particularly useful in an earth or ground station of satellite communication.
In satellite communication, a plurality of transponders are generally carried by each satellite. A frequency band is divided according to frequencies and assigned to the respective transponders. According to conventional satellite communication techniques, these transponders serve for individual communication links. In contrast, multi-transponder operation has recently been developed, wherein a plurality of transponders are simultaneously employed in a single communication link to raise flexibility and efficiency of operation of the whole single link.
On the other hand, recent improvements in the integrated circuit art have enabled highly developed digital communication techniques to be applied to satellite communication. For example, pulse code modulation-phase shift keying (PCM-PSK) is rendered readily applicable to time division multiple access (TDMA) satellite communication.
In a conventional device of the type set forth at the outset of the instant specification, use is made of space division switching techniques. An example is shown in FIG. 1 accompanying an article contributed by Y. Watanabe, one of the inventors of the present invention, to papers for "Third International Conference on Digital Satellite Communication," held Nov. 11 to 13, 1975, pages 385-393, under the title of "A New TDMA System for Domestic Service and its High Speed Modem," As will later be described with reference to one of several figures of the drawing accompanying the instant specification, use is necessary, in a conventional device of the type mentioned hereinabove, of a great number of transducers and a terribly great number of switching contacts. The conventional device is therefore bulky and expensive.